Question

I have set up a very simple code snippet:

$string = 'Some random words. Some more random, very random words.';
$words = explode(" ", $string);

for ($i = 0; $i < count($words); $i++) {
    $word = $words[$i];
    $words[$i] = str_replace(".", "!", $word);
    $words[$i] = str_replace(",", "?", $word);
}

print_r($words);

The output is this:

Array
(
    [0] => Some
    [1] => random
    [2] => words.
    [3] => Some
    [4] => more
    [5] => random?
    [6] => very
    [7] => random
    [8] => words.
)

Why only the second str_replace() function affect the string? If I remove the second str_replace() the first one works perfectly. It’s not about usage of str_replace() but I believe me doing something very very simply wrong.

By the way – I am aware of preg_replace() and passing an array to str_replace() but would like to hear about this particular situation :).

EDIT:
Thank you all for blazing quick responses. I am in a shame for such an issue but it really didn’t catch my eyes at first. Thanks everyone! I will accept the first correct answer by Mike Brant.

Answer 1

It is because your second statement uses $word as the subject of replacement and not $words[$i] which was where you assigned the string after the first replacement.

You can fix by either working directly with $words[$i] the entire time, or working exclusively with your temp variable and then making assignment like this:

for ($i = 0; $i < count($words); $i++) {
    $word = $words[$i];
    $word = str_replace(".", "!", $word);
    $words[$i] = str_replace(",", "?", $word);
}